import {KeyEvent as NKeyEvent, RegisterCallback, UnregisterCallback} from "tc-native/ppt";
import {EventType, KeyEvent, KeyHook, SpecialKey} from "tc-shared/PPTListener";
import {tr} from "tc-shared/i18n/localize";
import {LogCategory} from "tc-shared/log";
import * as log from "tc-shared/log";

let key_listener: ((_: KeyEvent) => any)[] = [];

function listener_key(type: EventType, nevent: NKeyEvent) {
    if(nevent.key_code === 'VoidSymbol' || nevent.key_code === 'error')
        nevent.key_code = undefined; /* trigger event for state update */

    let event: KeyEvent = {
        type: type,

        key: nevent.key_code,
        key_code: nevent.key_code,

        key_ctrl: nevent.key_ctrl,
        key_shift: nevent.key_shift,
        key_alt: nevent.key_alt,
        key_windows: nevent.key_windows
    } as any;

    for (const listener of key_listener)
        listener && listener(event);
}

function native_keyhook(event: NKeyEvent) {
    //console.log("Native event!: %o", event);

    if(event.type == 0)
        listener_key(EventType.KEY_PRESS, event);
    else if(event.type == 1)
        listener_key(EventType.KEY_RELEASE, event);
    else if(event.type == 2)
        listener_key(EventType.KEY_TYPED, event);
    else
        console.warn(tr("Received unknown native event: %o"), event);
}

export async function initialize() : Promise<void> {
    register_key_listener(listener_hook);
    RegisterCallback(native_keyhook);
}

export function finalize() {
    unregister_key_listener(listener_hook);
    UnregisterCallback(native_keyhook);
}

export function register_key_listener(listener: (_: KeyEvent) => any) {
    key_listener.push(listener);
}

export function unregister_key_listener(listener: (_: KeyEvent) => any) {
    const index = key_listener.findIndex(e => e === listener);
    if(index !== -1) key_listener.splice(index, 1);
}

let key_hooks: KeyHook[] = [];

interface CurrentState {
    keys: {[code: string]:KeyEvent};
    special: { [key:number]:boolean };
}
let current_state: CurrentState = {
    special: []
} as any;

let key_hooks_active: KeyHook[] = [];

function listener_hook(event: KeyEvent) {
    if(event.type == EventType.KEY_TYPED)
        return;

    let old_hooks = [...key_hooks_active];
    let new_hooks = [];

    current_state.special[SpecialKey.ALT] = event.key_alt;
    current_state.special[SpecialKey.CTRL] = event.key_ctrl;
    current_state.special[SpecialKey.SHIFT] = event.key_shift;
    current_state.special[SpecialKey.WINDOWS] = event.key_windows;

    current_state[event.key_code] = undefined;
    if(event.type == EventType.KEY_PRESS) {
        current_state[event.key_code] = event;

        for(const hook of key_hooks) {
            if(hook.key_code !== event.key_code) continue;
            if(hook.key_alt != event.key_alt) continue;
            if(hook.key_ctrl != event.key_ctrl) continue;
            if(hook.key_shift != event.key_shift) continue;
            if(hook.key_windows != event.key_windows) continue;

            new_hooks.push(hook);
            const index = old_hooks.findIndex(e => e === hook);
            if(index === -1 && hook.callback_press) {
                hook.callback_press();
                log.trace(LogCategory.GENERAL, tr("Trigger key press for %o!"), hook);
            }
        }
    }

    //We have a new situation
    for(const hook of old_hooks) {
        //Do not test for meta key states because they could differ in a key release event
        if(hook.key_code === event.key_code) {
            if(hook.callback_release) {
                hook.callback_release();
                log.trace(LogCategory.GENERAL, tr("Trigger key release for %o!"), hook);
            }
        } else {
            new_hooks.push(hook);
        }
    }
    key_hooks_active = new_hooks;
}


export function register_key_hook(hook: KeyHook) {
    key_hooks.push(hook);
}

export function unregister_key_hook(hook: KeyHook) {
    let index;

    index = key_hooks.findIndex(e => e === hook);
    if(index !== -1) key_hooks.splice(index, 1);

    index = key_hooks_active.findIndex(e => e === hook);
    if(index !== -1) key_hooks_active.splice(index, 1);
}

export function key_pressed(code: string | SpecialKey) : boolean {
    if(typeof(code) === 'string')
        return typeof(current_state[code]) === "object";
    return current_state.special[code];
}